Resized case length vs fired length

[noone]

I have one Grendel, and one 6.5CSS. I set my die so that the shoulder of the shorter chamber gets set back .002. That way, the longer chamber only gets set back about .003 or .004. I am more likely to have malfunctions if the bullet is seated too far into the rifling than from the shoulder not fitting. And I let the rifles get pretty dirty prior to cleaning them.